Abstract:

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The mechanical behaviors were investigated by nonlinear creep tests of poly(methyl
methacrylate) under different temperatures. The test duration was 4000 seconds. The corresponding
temperature shift factors, stress shift factors and temperature-stress shift factors were obtained
according to time-temperature superposition principle, the time-stress superposition principle and
the time-temperature-stress superposition principle (TTSSP). The master creep compliance curve up
to about 1-month at a reference temperature 22 degrees centigrade and a reference stress 14 MPa
was constructed, and the effect of stress-induced damage evolution on the long-term creep behavior
of polymeric material was accounted. It was shown that TTSSP provides an effective accelerated
test technique in the laboratory, the results obtained from a short-term creep test of poly(methyl
methacrylate) specimen at high temperature and stress level can be used to construct the master
creep compliance curve for prediction of the long-term mechanical properties at relatively lower
temperature and stress level, and the master creep compliance curve with damage considered can be
applied to accurately characterize the long-term creep behavior of nonlinear viscoelastic polymer.